1. Field of the Invention
The invention relates generally to methods for producing electronic devices, and more specifically, to methods for producing undercut regions in substrate structures.
2. Description of the Related Art
Organic electronic devices have attracted increasing attention in recent years. Examples of organic electronic device include Organic Light-Emitting Diode (“OLED”) displays. Organic active layers can be deposited over a substrate using ink-jet printing. A substrate structure is typically formed as a physical barrier to confine the red, green, and blue materials to separate pixels or subpixels. These substrate structures are often formed using an organic material such as a positive or negative photoresist material. However, when developers are introduced to pattern the photoresist material, Galvanic coupling reactions can occur with the underlying electrode resulting in a damaged pixel or subpixel. Often an insulation process using a dielectric material is used to protect the underlying electrode during patterning of the substrate structure, but this process is time consuming. In addition, the dielectric material must be completely removed before the organic layers are deposited, otherwise the pixel or subpixel will not function. This removal of the dielectric material is typically performed using a Reactive Ion Etch (RIE) which can easily damage the underlying electrode if not stopped precisely when all of the dielectric material has been removed.
In order to form an active layer with a uniform thickness within each pixel or subpixel, accurate deposition of the ink and proper design and treatment of the substrate structures is generally required. However, surface treatments of the substrate structures, such as plasma treatment, can easily damage the underlying electronic components in, for instance, an active matrix substrate. It has proven quite challenging to develop manufacturing processes for organic electronic devices that maintain peak device performance while using surface treatment for substrate structures and at the same time providing uniform deposition of organic materials into the pixels or subpixels.